In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed.
For example, one parameter in providing good performance and capacity for a given communications protocol in a communications network is the ability to provide efficient and reliant liveness check, also called dead peer detection, for example over untrusted non-3GPP access networks, where 3GPP is short for the Third Generation Partnership Program.
Liveness check enables ensuring that both ends of an Internet key exchange (such as Internet key exchange v1, IKEv1, or Internet key exchange v2, IKEv2) security association are alive.
In general terms, a liveness check may involve one endpoint of the Internet key exchange security association sending an informational request message with no payloads (other than the empty encrypted payload required by the syntax) to which the other endpoint of the Internet key exchange security association responds with an informational response message. The protocol according to the IETF (Internet Engineering Task Force) RFC (Request for Comments) 5996 expects that the informational request message is sent periodically, if the endpoint has not received any cryptographically protected Internet protocol security (IPSec) or Internet key exchange packet as part of the Internet key exchange security association for a given timeout.
When Internet key exchange is used in an untrusted access network, a user equipment and an evolved packet data gateway (ePDG) act as endpoints of the Internet key exchange security association.
The ePDG can send the informational request message to monitor the liveness of the user equipment, but this requires timers in the ePDG.
The user equipment can send the informational request message to monitor the liveness of the ePDG, but the operator has no control of what the timeout is. Hence, there is a limited possibility for the network to control the actual usage of liveness check from the user equipment.
Hence, there is a need for an improved liveness check of user equipment.